Hyper-elastic needle

ABSTRACT

The invention concerns a surgical needle comprising a crimping region ( 3 ) for fixing a suture ( 5 ) made of hyper-elastic alloy having, after treatment, two different states enabling to stress the needle in a substantially elongated position when it is housed in the internal bore ( 11 ) of a cannula or of an applicator ( 2 ) and when it is extracted from the cannula or the applicator to adopt an arc-shaped curved profile as a result of its own particular super-elastic or hyper-elastic properties, and the needle ( 1 ) comprises opposite the crimping zone ( 3 ) a tapered tip ( 6 ) provided with an inclined heel ( 7 ) arranged inside the curvature of the needle ( 1 ) and which is urged to be pressed against the internal wall of the bore ( 11 ) of the cannula or the applicator ( 2 ) to protect the tapered tip profile ( 6 ) when the needle is sliding inside the internal bore ( 11 ).

[0001] The present invention relates to surgical needles manufactured from hyper-elastic alloys and which are intended to be used in celioscopy or endoscopy procedures.

[0002] Patent EP 0 529 675 of Aug. 31, 1992 in the name of ETHICON INC., describes a surgical needle made of a shape memory alloy which has a low-temperature first state and a high-temperature second state.

[0003] In its low-temperature state, the needle can be configured into an elongate shape so as to allow it to be slipped into a straight tube.

[0004] In its high-temperature state, the needle forms a predetermined arc while the needle is designed to be used as a surgical needle.

[0005] The needle according to patent EP 0 529 675 is particularly well-suited to endoscopy procedures in which elements are taken to the site of surgery via a cannula or trocar which have a small-sized internal diameter.

[0006] The needle described in patent EP 0 529 675 does exhibit certain drawbacks regarding the need to bring the body of the needle arranged at the site of the operation up beside a source of heat in order to cause it to adopt a configuration which is curved into a predetermined arc.

[0007] It is also found that the tapered point of the needle runs the risk of becoming damaged inside the cannula as it is introduced to the site of the operation. What happens is that the small diameter of cannulas, approximately 5 mm, and the somewhat elongate shape of the needle, necessarily lead to its point, which is fragile, being rubbed against the interior wall of the cannula.

[0008] Damage to the tapered point of the needle is irreparable because the surgeon can no longer use it, and this forces him to introduce another needle, taking all possible skillful precautions not to damage it.

[0009] The surgical needle according to the present invention is intended to define the profile of the tapered point so that the latter does not become damaged against the interior wall of the cannula or of a special applicator of which the inside diameter housing the needle is between 1 and 2 millimeters.

[0010] The surgical needle according to the present invention is made of a hyper-elastic alloy which, after treatment, has two distinct states making it possible, on the one hand, to force the needle into a roughly elongate position when it is housed in the internal bore of a cannula or of an applicator and, on the other hand, when it is extracted from the cannula or from the applicator, to adopt a curved profile in the shape of an arc of a circle because of its own characteristics of superelasticity or hyper-elasticity, and in that the needle comprises, at the opposite end to the suture crimping zone, a tapered point provided with an inclined heel which is arranged inside the curvature of the needle and which bears against the interior wall of the bore of the cannula or of the applicator to protect the profile of the tapered point as said needle slides inside the internal bore.

[0011] The surgical needle according to the present invention is made of a hyper-elastic alloy which contains about 54% to 58% of nickel and about 42% to 46% of titanium.

[0012] The surgical needle according the present invention is made of a hyper-elastic alloy which is made up essentially of nickel, titanium and a small amount of chromium, or iron, or zirconium, modifying either the transformation temperature or the hardness of said alloy.

[0013] The surgical needle according to the present invention is made of a hyper-elastic alloy which undergoes a heat treatment under stress, the temperature of which is between 400° C. and 600° C. for 15 to 60 minutes, followed by a sudden quenching in air or water at between 0° C. and 3° C.

[0014] The surgical needle according to the present invention comprises a crimping zone which is pierced with an internal blind hole intended to house a suture.

[0015] The surgical needle according to the present invention comprises a crimping zone which may, in certain cases, undergo annealing at a temperature of 500° C., followed by slow cooling, after shaping.

[0016] The surgical needle according to the present invention comprises a heel which is inclined by an angle α which depends on the internal diameter of the cannula or of the applicator, on the diameter and on the length of the needle.

[0017] The surgical needle according to the present invention has a cross-sectional profile of triangular shape, one of the vertices of which triangle constitutes the outer edge of the arc of a circle of the needle.

[0018] The surgical needle according to the present invention comprises a heel which lies on the inside of the curvature of the needle and on the opposite side to the outer edge of the triangular profile.

[0019] The surgical needle according to the present invention comprises a crimping zone which has a cross-sectional profile of circular shape.

[0020] The surgical needle according to the present invention comprises, between the crimping zone and the tapered point, a cross-sectional profile of roughly square or rectangular shape.

[0021] The description which will follow, with reference to the appended drawings which are given by way of non-limiting example, will allow a better understanding of the invention, of the characteristics it has and of the advantages it is able to afford:

[0022]FIG. 1 is a view illustrating the needle made of hyper-elastic alloy according to the present invention.

[0023]FIG. 2 is a view showing, in detail, the tapered point of the needle according to the present invention.

[0024]FIG. 3 is a view depicting the hyper-elastic needle forced to an elongate position inside the applicator for placement at the site of the operation.

[0025]FIG. 4 is a view similar to that of FIG. 3 but illustrating the needle extracted from the applicator.

[0026]FIG. 5 is a view showing, in detail, the position at the tapered point of the needle inside the applicator.

[0027]FIGS. 1 and 2 show a needle 1 made of a hyper-elastic alloy based on nickel (Ni) and titanium (Ti) and which, after the alloy has been treated, has two distinct states.

[0028] In the first state, the needle 1 can be forced into a roughly elongate position so as to be arranged inside a cannula or applicator 2.

[0029] In the second state, that is to say when the stress is removed, the needle 1 is shaped into a profile in the shape of an arc of a circle for use at the site of the surgery.

[0030] The switch from the first state to the second is inherent in the characteristics of the alloy which is treated so that it has characteristics of superelasticity or hyper-elasticity.

[0031] The composition of the nickel/titanium alloy varies from 54% to 58% nickel, the remainder being titanium, that is to say from 42% to 46%. Other elements such as chromium (Cr), iron (Fe) and zirconium (Zr) may also be added in very small percentages to modify either the transformation temperature or the hardness.

[0032] The shaping of the needle consists in applying a heat treatment under stress (400° C. to 600° C. for 15 to 60 minutes), followed by sudden quenching in air or water (0° C. to 3° C.).

[0033] The needle 1 comprises a crimping zone 3 which is pierced with an internal bind hole 4 intended to accommodate a suture 5 prior to crimping.

[0034] In certain cases, the crimping region 3 may undergo annealing (at 500° C. followed by slow cooling) after shaping. This heat treatment is intended to locally eliminate the elasticity of the alloy with a view to improving the retention of the suture 5 in the needle 1.

[0035] At the opposite end to the crimping zone 3, the needle 1 has a free end which is shaped with the profile of a tapered point 6. The tapered point 6 of the needle 1 can be thinned or have any other shape.

[0036] The tapered point 6 comprises a heel 7 which is arranged on the inside of the curvature in the shape of an arc of a circle of the needle 1.

[0037] The heel 7 is inclined by an angle α with respect to a horizontal tangent which depends on the internal diameter of the cannula or of the applicator 2, on the diameter and on the length of the needle 1.

[0038] Also, the needle 1 may be manufactured in all shapes known to the art of surgery. For example, the needle 1 may, in cross section, have a circular, square, rectangular or triangular profile.

[0039] A cross-sectional profile of triangular shape has been adopted as a preference for the tapered point 6, one of the vertices of which triangle constitutes the outer edge of the circular arc of the needle 1. In this case, the heel 7 is situated on the inside of the curvature of the needle 1 and on the opposite side to the outer edge of the triangular profile.

[0040] The needle 1 has, at the crimping zone 3, a cross-sectional profile of circular shape, whereas the remainder of the body of the needle which lies between the tapered point 6 and the said crimping zone 3 has a cross-sectional profile of roughly square or rectangular shape.

[0041] The roughly square or rectangular cross-sectional profile of the body of the needle 1 allows the surgeon to grasp it with greater ease in forceps or a needle holder.

[0042]FIG. 3 depicts the applicator 2 for the placement of the needle 1 secured to its suture 3 at the site of the surgery using a trocar 8 which has already been placed through the wall 9 of a patient.

[0043] This applicator has been described and protected in a French patent No. 97 07681 of which the applicant is the proprietor.

[0044] The applicator 2 comprises a cylindrical sleeve 10 pierced along its entire length and parallel to its longitudinal axis with a bore 11 in which the needle 1 and its suture 5 are housed.

[0045] The sleeve 10 comprises at one of its ends a cylindrical head 12 which is given a diameter greater than that of the remainder of the body of said sleeve.

[0046] The needle 1 is arranged in the bore 11 of the sleeve 10 in such a way that its tapered point 6 faces toward the free end 13 and away from the end with the head 12.

[0047] The applicator 2 comprises a rod 14 which is secured at one of its ends to a cylindrical stop 15.

[0048] The rod 14 is introduced into the sleeve 10 in such a way as to bear against the needle 1. The rod 14 passes through the bore 11, so that the suture 5 is arranged between said rod and the wall of said bore.

[0049] Retaining means 16 allow the rod 14 to be held in position with respect to the sleeve 10, so that the free end of the rod 14 which is the opposite end to the stop 15, always presses against the needle 1.

[0050] The applicator 2 is arranged inside the trocar 8 which has already been placed through the wall 9 of a patient.

[0051] The trocar consists of a tube 17 secured at one of its ends to a circular skirt 18 acting as a stop for the applicator when the needle 1 is placed at the site of the surgery as will be seen better later on.

[0052] The tube 17 of the trocar 8 is designed to accommodate the sleeve 10 of the applicator 2, while the head 12 bears against the circular skirt 18.

[0053] The surgeon then withdraws the retaining means 16 in order to release the rod 14 with respect to the sleeve 10.

[0054]FIG. 4 shows the extraction of the needle 1 from the sleeve 10 of the applicator 2.

[0055] What happens is that all the surgeon needs do is to press, in the direction of the arrow F, on the stop 15 of the rod 14, so as, via said rod 14, to push the needle 1 out of the sleeve 10. The displacement of the rod 14 is limited in its travel to the point where the stop 15 is in contact with the head 12 of the sleeve 10.

[0056] When the needle 1 is extracted from the sleeve 10 of the applicator, this needle, because of its elasticity, adopts its circular-arc shape, allowing the surgeon to suture.

[0057]FIG. 5 shows the position of the tapered point 6 of the needle 1 inside the bore 11 of the sleeve 10 of the applicator 2.

[0058] It can be seen that the heel 7 allows the tapered point 6 of the needle to be protected as it moves or slides inside the bore 11 of the sleeve 10.

[0059] What happens is that only the heel 7, and more particularly, the point where it meets the curved part of the needle 1, is in contact with the internal wall of the bore 11 of the sleeve 10, thus protecting the tapered point 6 against any damage due to rubbing.

[0060] It goes without saying that the applicator 2 may be replaced by a cannula or a trocar which are known per se for the placement of the needle 1 inside the operating site, without that in any way changing the subject of the present invention. 

1. A surgical needle comprising a crimping zone (3) for securing a suture (5), characterized in that it is made of a hyper-elastic alloy which, after treatment, has two distinct states making it possible, on the one hand, to force the needle into a roughly elongate position when it is housed in the internal bore (11) of a cannula or of an applicator (2) and, on the other hand, when it is extracted from the cannula or from the applicator, to adopt a curved profile in the shape of an arc of a circle because of its own characteristics of superelasticity or hyper-elasticity, and in that the needle (1) comprises, at the opposite end to the crimping zone (3), a tapered point (6) provided with an inclined heel (7) which is arranged inside the curvature of the needle (1) and which bears against the interior wall of the bore (11) of the cannula or of the applicator (2) to protect the profile of the tapered point (6) as said needle slides inside the internal bore (11).
 2. The surgical needle as claimed in claim 1, characterized in that the hyper-elastic alloy contains about 54% to 58% of nickel and about 42% to 46% of titanium.
 3. The surgical needle as claimed in claim 2, characterized in that the hyper-elastic alloy is made up essentially of nickel, titanium and a small amount of chromium, or iron, or zirconium, modifying either the transformation temperature or the hardness of said alloy.
 4. The surgical needle as claimed in claim 1, characterized in that the hyper-elastic alloy of which the needle (1) is made undergoes a heat treatment under stress, the temperature of which is between 400° C. and 600° C. for 15 to 60 minutes, followed by a sudden quenching in air or water at between 0° C. and 3° C.
 5. The surgical needle as claimed in claim 1, characterized in that it comprises a crimping zone (3) which is pierced with an internal blind hole (4) intended to house a suture (5).
 6. The surgical needle as claimed in claim 5, characterized in that the crimping zone (3) may, in certain cases, undergo annealing at a temperature of 500° C., followed by slow cooling, after shaping.
 7. The surgical needle as claimed in claim 1, characterized in that the heel (7) is inclined by an angle α which depends on the internal diameter of the cannula or of the applicator (2), on the diameter and on the length of the needle (1).
 8. The surgical needle as claimed in claim 1, characterized in that, at the tapered point (6), it has a cross-sectional profile of triangular shape, one of the vertices of which triangle constitutes the outer edge of the arc of a circle of the needle (1).
 9. The surgical needle as claimed in claim 8, characterized in that the heel (7) lies on the inside of the curvature of the needle (1) and on the opposite side to the outer edge of the triangular profile.
 10. The surgical needle as claimed in claim 1, characterized in that, in the crimping zone (3), it has a cross-sectional profile of circular shape.
 11. The surgical needle as claimed in claim 1, characterized in that, between the crimping zone (3) and the tapered point (6), it has a cross-sectional profile of roughly square or rectangular shape. 